We have prepared recombinant adenoviral vectors to deliver SIV genes into dendritic cells (DCs) for eventual use as adjuvants in eliciting resistance to SIV. DCs are potent antigen presenting cells that can be prepared from precursor monocytes in macaque blood. Two constructs, adenovirus-gag and adenovirus-nef each with a GFP reporter, were prepared and produced at high titer. We found that these adenoviruses could infect DCs efficiently, particularly if we infected the more immature stages of DC development. These DCs were produced by culturing T-depleted monkey blood leukocytes in GM-CSF and IL-4 for 6-7 days. Following infection, the DCs were exposed to macrophage-derived cytokines or to lipopolysaccharide to produce mature, potent, T cell stimulatory DCs. The efficiency of infection was >90%, and the expressed SIV gag and nef gene products could be visualized by immunoperoxidase and western blot. Adenoviral infection did not alter the viability and function of DCs. The recombinant adenoviruses were presented well to CD8+ T cells, as shown by an elispot assay for interferon-gamma release. Adenoviral vectors can now be compared to other vectors, e.g., canary pox, for presentation of SIV antigens to T cells in culture and in animals. FUNDING NIH (R01 AI42129) PUBLICATIONS Steinman, R.M. and R.N. Germain. Antigen presentation and related immunological aspects of HIV-1 vaccines. AIDS, 12:S97-S112, 1998.